1. Field of the Invention
The present invention relates to a device suitable for the simultaneous disinfection and removal of nitrate/nitrite ions as well as other adsorbable organic impurities present in small quantities of drinking water. The present invention also relates to a process for the simultaneous disinfection and removal of nitrate/nitrite ions as well as other adsorbable organic impurities present in small quantities of drinking water.
2. Description of the Related Technology
Nitrates are, in addition to being found in ever-increasing amounts in drinking water, naturally present in food products, notably those of plant origin.
The toxicity of a nitrate rises considerably if reduced to a more harmful nitrite. This reduction can occur in a variety of ways, for example:
1) by the presence of nitrate-reducing bacteria in the gastro-intestinal tract, and
2) by the presence of nitrate-reducing micro-organisms in water-treatment systems, for example, those used domestically.
The increase of nitrate concentrations in drinking water, added to the presence of pesticides and insecticides that has been occasioned by the wasteful practices of the past, is today causing growth concern throughout the world. In addition to the problems posed by the presence of such toxic substances in water supplies is the continuing need to secure bacteria-free water supplies. Industrialized countries, furthermore, are experiencing a growing demand for the treatment of smaller supplies of drinking water, such as are used for example in preparing baby formulas, on travel or camping trips. In third-world countries, the treatment of smaller quantities of water is of great importance, since up to the present, the majority of cities and towns in those countries often procure their drinking water from unreliable sources of supply.
This fact increases the urgency of finding a means of treating limited quantities of drinking water which, in a cost-effective and simple manner, is capable of removing bacteria, nitrates or nitrites and, last but not least, harmful organic impurities. An ideal purification process would not involve adding chemical products to the already overloaded water. A review of the currently-available systems or methods employed to disinfect water or remove nitrate/nitrite ions has demonstrated, however, that there currently exists no practical system capable of addressing the above-mentioned concerns. Although there are presently a number of water-filtration systems on the market, these are nothing more than anion/cation exchanges, which, by removing all present anions and cations are able to produce pure, distilled water. Nutritional science teaches us however, that distilled water was never suited for the human palate, and could even pose a threat to health.
There also currently exist on the market numerous apparatuses for softening or simply filtering drinking water destined for household consumption. During operation of these systems however, the micro-organisms normally present in the supplied water collect and multiply inside the apparatus itself. If none of these filtration systems has there been any provision made for the removal of such accumulated micro-organisms after prolonged periods of use. This can reduce the effectiveness of such systems to the point of their becoming unuseful.
It is known that ion exchangers, due to their highly porous structure, constitute an ideal breeding side for bacteria.
It is further recognized that such prior art ion exchangers, which are preferably embodies in the form of small spheres, are, when loaded with nitrate ions, quite susceptible to becoming sites for bacterial growth.
The nitrate concentrations in drinking water are constantly on the increase throughout the world. In many cases, the reason for such high concentration lies in the intensive over-fertilization of agricultural soils. Any nitrogen that is not absorbed by either the soil or plants is washed away, enters the ground or surface water systems and then the food chain.
The admissible limit for nitrate concentration in drinking water has been set in European countries at 25 mg/l. Because many drinking-water sources have concentrations surpassing these limits, there exists in practically all of these countries a growing need for a safe and easy-to-operate filtration device for the treatment of water used for drinking purposes and for the preparation of food products that are free of harmful substances.
The removal of nitrate ions with the aid of ion exchanging systems is known in the art. One problem, however, is that of keeping the ion exchanger free of bacteria and maintaining such a system bacteria-free throughout repeated use cycles.